NL8702632A - POLYCARBONATE WITH LOW RELATIVE VISCOSITY AND POLYMER MIXTURES. - Google Patents

Description

,! 5 (i * ♦ 8-CB-10.312 -1-1 General Electric Company of Schenectady, New York,

United States.

Applicants cite L.P.J. of the 5 Watering and Jan de Boer.

*

Low relative viscosity polycarbonate and polymer blends.

The invention relates to an aromatic polycarbonate with terminal 4-cumylphenyl groups.

Aromatic polycarbonate is a known polymer. Chain-stop agents for controlling the molecular weight of the polymer are used in the preparation of aromatic polycarbonate.

The most commonly used chain stopper is phenol. The use of 4-cumylphenol as chain stopper is known from JP-A-57 (1982) -133149. The use of chain stop agents leads to the incorporation into the polymer of terminal groups derived from the chain stopper (namely 4-cumylphenyl groups).

25

It is well known that the flow properties of polymers can be improved by decreasing the molecular weight of the polymer. Limits are imposed on this reduction: if the molecular weight is reduced too far, the mechanical properties of the polymer decrease. This also applies to aromatic polycarbonate. Low molecular weight aromatic polycarbonate (corresponding to a relative viscosity of less than 1.23) has a much lower notch impact value at room temperature than normal polycarbonate with; a relative viscosity of, for example, 1.29.

.8702632 8-CB-10.312 -2-1 The invention is based on the discovery that aromatic polycarbonate with terminal 4-cumylphenyl groups also has good mechanical properties at a low molecular weight / such as a good impact strength / especially also at reduced temperatures. .

In general, the impact strength of a polycarbonate drops sharply when the polycarbonate 10 is mixed with an inorganic filler / pigment.

The polycarbonate according to the invention has the surprising property that it retains its impact strength after mixing with titanium dioxide.

The aromatic polycarbonate according to the invention is characterized in that it has a relative viscosity of less than 1.23. Preferably, the relative viscosity is between 1.19 and 1.23.

The polycarbonate powder according to JP-A-57 (1982) -133419 has a molecular weight of 24/700 to 25/600 which corresponds to a relative viscosity of about 1.25-1.28.

The invention also relates to an aromatic polycarbonate as defined in claim 1 / which is mixed with 0-10 wt% titanium dioxide.

, 8702632 4 / * 8-CB-10.312-3-1 The aromatic polycarbonate according to the invention can also be used in polymer mixtures. The invention also relates to such mixtures.

Of particular interest are the polymer mixtures containing the aromatic polycarbonate according to the invention and one or more agents for improving the impact strength.

It has been found that addition of a relatively small amount of 0.1-4 weight percent of one or more impact enhancers results in polymer blends that combine good flow with good impact strength at low temperatures.

Larger amounts of impact strength improving agent result in deterioration of flow.

Preferably, in the polymer mixture according to the invention, a mixture of two different agents for improving the impact strength is used, namely a mixture of: B1. a core-shell graft copolymer composed of a rubber-like core / mainly composed of an acrylate rubber or a butadiene rubber and one or more grafted shells of a rigid polymer grafted thereon mainly composed of an alkyl acrylate and / or alkyl methacrylate and / or vinyl laromatic compound such as styrene and / or acrylo-nitrile and B2. a block copolymer composed of rubbery silicone blocks and polycarbonate blocks.

.8701632 8-CB-10.312 -4-1 In addition to the impact strength enhancers mentioned above, the polymer mixture of the invention may contain one or more of the following ingredients: one or more flame retardant enhancers. properties / one or more stabilizers / one or more agents for reducing the droplet (drip) properties in flame tests / one or more pigments / one or more dyes / one or more fillers / one or more reinforcing fibers such as glass fibers / lubricants / release agents / plasticizers.

The aromatic polycarbonate according to the invention itself can also be mixed with the above-mentioned components / without using agents to improve the impact strength.

The polymer mixture according to the invention may in particular also contain pigments such as titanium dioxide / for example in an amount of 0.1-10 parts by weight per 100 parts by weight of the aromatic polycarbonate according to the invention plus the agent or agents for improving the impact strength. It has been found that the addition of titanium dioxide only leads to a very small decrease in the notch impact value.

The polymer mixture according to the invention may additionally contain further polymers such as polyalkylene terephthalates, for example polybutylene terephthalate. It is preferred to use / when using polyalkylene terephthalates / 1-100 parts by weight of the polyalkylene terephthalate per 100 parts by weight of the aromatic polycarbonate of the invention plus the agent or agents for improving the impact strength.

.8702632 »8-CB-10.312 -5- 1 The invention finally also relates to objects formed from the aromatic polycarbonate according to the invention or from the polymer mixture according to the invention.

5

The aromatic polycarbonate according to the invention

Aromatic polycarbonates are known per se polymers. They are usually prepared by a so-called interfacial polymerization process. Thereby, phosgene is passed through an aqueous alkaline solution of a dihydric phenol in the presence of an inert organic solvent. Usually a chain stopper is added during or shortly before the end of the reaction. In the preparation of the aromatic polycarbonate according to the invention, 4-cumylphenol is always added as a chain stopper.

It is possible to control the molecular weight of the polycarbonate by dosing the amount of chain stopper and by choosing the time at which the chain stopper 20 is added to the reaction mixture. For the preparation of the polymer according to the invention, this is controlled in such a way that a polycarbonate with a relative viscosity of less than 1.23 is obtained. Relative viscosity is here always used to refer to the relative viscosity according to DIN standard 7744 part 2r at a concentration of 0.5 g polymer dissolved in 100 ml dichloromethane at 25 ° C. Measurements were always made with a 30 Ubelohde viscometer with a so-called Oc capillary.

. 87026 32 ί «8-CB-10.312 -6- 1 It is also possible to obtain a polycarbonate according to the invention by mixing two or more different polycarbonates. For example, by mixing / in approximately equal amounts of weight a polycarbonate with a relative viscosity of 1.24 with a polycarbonate with a relative viscosity of 1.20. Both polycarbonates must have terminal 4-cumylphenyl groups.

As indicated above, the polymer mixture according to the invention contains the aromatic polycarbonate according to the invention and one or more agents for improving the impact strength.

Adding one or more impact improving agents to the polycarbonate of the invention results in a polymer blend having good flow and good impact strength at low temperatures. For this purpose it is only necessary to add relatively small amounts of the agent or agents for improving the impact strength.

To obtain the same good impact strength at low temperatures for polymer blends based on a polycarbonate of the same low relative viscosity but with phenyl terminal groups, it is necessary to add larger amounts of the impact strength improving agent. However, this usually leads to a deterioration of the flow properties.

.8702632 * 8-CB-10.312 -7- * 1 In the polymer mixtures according to the invention, a mixture of two impact improving agents is preferably used, namely a mixture of: 5 B1. a core-shell graft copolymer composed of a rubber-like core / mainly composed of an acrylate rubber or a butadiene rubber and one or more grafted shells of a rigid polymer grafted thereon mainly composed of an alkyl acrylate and / or alkyl methacrylate and / or vinyl aromatic compound such as styrene and / or acrylonitrile and B2. a block copolymer composed of rubbery silicone blocks and polycarbonate blocks.

15

Core-shell graft copolymers as referred to above are well known. For this, reference can be made, for example, to US-A-3 / 426,101; US-A-3/655/826; US-A-4096202; US-A-4,180,494.

20

Block copolymers constructed from rubbery silicone blocks and polycarbonate blocks are also known. For this, reference can be made, for example, to US-A-2 999 845; OS-A-3189 662; US-A-3,419 / 634; US-A-3,679,774 and EP-A-0193757.

The polymer mixture of the invention can be prepared by any of the conventional methods of preparing polymer mixtures. Preferably, the polymer mixture according to the invention is prepared by compounding in an extruder.

The invention is illustrated by the following examples.

.8702632 e * 8-CB-10.312 -8- 1 Example I.

The preparation of an aromatic polycarbonate.

From aromatic phenol and phosgene, various aromatic polycarbonates were prepared by interfacial polymerization. A chain stopper was always used in the preparation: in the preparation of polymers A and B 4-cumylphenol and in the preparation of polymers C and D phenol. The chain stopper was used at a concentration of 6.2 mol% for polymer k, 4.7 mol% for polymer B, 6.2 mol% for polymer C and 4.6 mol% for polymer D.

Thus, four polymers were obtained with a relative viscosity as indicated in table Ά.

The notched impact value according to Izod was measured at different temperatures. The results are also shown in Table A.

The melt flow index (MFI) was also determined according to DIN 53735 or ISO 1133 at 300 ° C under a load of 12 N for 10 minutes.

.8702632 8 — CB — 10,312 -9- -¾

1 Polymer A BCD

End group 4-cumylphenyl 4-cumylphenyl phenyl phenyl 5 o relative 1.98 1,232 1,198 1,248 viscosity o MFI 55 25 50 20 10 o Izod notched impact value (J / m)

Room temp. 300 620 110 620 0eC 100 510 100 120 15 -10 ° C 100 250 100 100 -20 ° C 100 170 100 170 20

Example IX.

Polymer A was compounded with various amounts of barium sulfate in an extruder.

The same was done with polymer C. Thus, different compositions were obtained. Test statues for measuring the notched Izod impact strength were injected from these compositions. The notch impact value of these bars was determined. The different compositions and the corresponding impact strength values are included in Table B.

£ 702632

V

8-CB-8-CB-10.312 -ΙΟ Ι Table Β.

IZOD Notch Impact Value

Polymer A (J / m; room temp.) + 0 wt% BaS04 656 5 +1 wt% BaS04 170 + 3 wt% BaS04 158

Polymer C

+ 0 wt% BaS04 625 10 +1 wt% BaS04 245 + 3 wt% BaS04 135

It can be seen from Table B that the polymer according to the invention (polymer A), like the known polymer (polymer C), has a poor notch impact value after mixing with barium sulphate.

The above-mentioned polymers A and C were then compounded with different amounts of titanium dioxide. The notch impact value was again determined. The results are shown in Table C.

Table C.

IZOD Notched impact value 25 Polymer A (J / m; room temp.) + 0 wt% T1O2 ® ^ 6 + 1 wt% T1O2 ^ 43 + 2 wt% Ti02 634 + 5 wt% T1O2 636 30

Polymer C

+ 0 wt% T1O2 633 + 1 wt% T1O2 54 * + 2 wt% T1O2 * ^ 4, 8702632 8-CB-10.312 -11- 1 From Table C it can be seen that the polymer according to the invention (polymer A) is only very sensitive to mixing with titanium dioxide. The known polymer C, on the other hand, exhibits a very high sensitivity to titanium dioxide.

Example III.

Different polymer mixtures were prepared using, on the one hand, a mixture of equal parts by weight of polymer A and polymer B and, on the other hand, polymer C and polymer D (according to example I). The mixtures thus obtained were each compounded into a polymer mixture in an extruder with two different agents to improve impact strength and with a mixture of these two agents. The following ingredients were used as an agent for improving the impact strength: Paraloid® KM 653: a core-shell copolymer commercially available from Rohm & Haas with a core based on a butadiene rubber and with a shell mainly composed of Methyl methacrylate and styrene.

LR 3320: a commercially available from

General Electric Company polycarbonate-polysiloxane block copolymer with blocks containing about 30 siloxane units.

For the polymer mixtures obtained, the notched impact value according to IZOD at different temperatures / the flexed plate impact according to DIN 53443 35 at -30 ° C and the melt flow index was determined. Also determined the transition temperature between ductile and brittle fracture (D / B).

8702632 * 8-CB-10.312 -12- 1 The results are summarized in Table D below for the polymer mixtures based on a polymer according to the invention (with 4-cumylphenyl-terminal groups). Table E shows the results for polymer mixtures based on a polymer with the same intrinsic viscosity but with a terminal group (phenyl group) not according to the invention.

10 Table D.

Composition No. 1234567 (parts by weight) 15 Polycarbonate A 50 50 50 50 50 50 50

Polycarbonate B 50 50 50 50 50 50 50 LR 3320 - 0.5 1.5 - - 0.5 1.5 KM 653 - 0.5 1.5 1.0 1.0 20 Properties

Izod notched impact strength (J / m)

Room temperature 621 621 619 639 601 615 599 10 ° C 502 591 585 585 562 584 563 0eC 462 261 306 313 460 473 533 25 -5 ° C 156 216 215 465 526 475 520 -10 ° C 159 146 175 143 294 199 461 - 15 ° C 204 177 349 -20 ° C ------ 223

Flexed Plate Impact (J) 30 -30 ° C 102 97 91 119 108 117 123 MFI (g / 10 min.) 39 38 37 37 39 38 39 D / B (° C) -2 5 -2 -7 -7 - 7 -17 .9702632 8-CB-10.312 -13- 1 Table E.

Composition no. 8 9 10 11 12 13 14 (parts by weight) 5

Polycarbonate C 50 50 50 50 50 50 50

Polycarbonate D 50 50 50 50 50 50 50 LR 3320 - 0.5 1.5 - - 0.5 1.5 KM 653 - 0.5 1.5 1.0 1.0 10

Characteristics

Izod notched impact strength (J / m)

Room temperatures 103 347 570 212 620 590 610 10 ° C 97 222 179 117 340 487 566 15 0eC 103 120 137 105 159 181 210

Flexed Impact (J) -30 ° C 91 109 113 86 88 106 103 20 MFI (g / 10 min.) 37 38 36 39 38 38 38 D / B (eC)> RT RT 15> RT 10 5 5 * RT = room temperature.

From a comparison of the results shown in Tables D and E, it can be seen that the polycarbonate according to the invention and that polymer blends based on that polycarbonate have a better combination of low temperature impact strength and flow than the known polycarbonate. The D / B temperatures are about 15 ° C lower at the same flow. If one wishes to give the polymer mixtures according to Table E an equal low temperature impact strength, a larger amount of LR 3320 and / or KM 653 would have to be added; this would lead to a sharp increase in melt viscosity and an unacceptable increase in melt flow index.

.8702632

Claims (8)

8-CB 10.312 -14- 1 Conclusions. BI. a core-shell graft copolymer composed of a rubber-like core / mainly composed of an acrylate rubber or a butadiene rubber and one or more grafted shells of a rigid polymer grafted thereon mainly composed of an alkyl acrylate and / or alkyl methacrylate and / or vinyl laromatic compound such as styrene and / or acrylonitrile and 10 B2. a block copolymer composed of rubbery silicone blocks and polycarbonate blocks. 1. Aromatic polycarbonate with 4-cumylphenyl end groups / characterized in that the aromatic polycarbonate has a relative viscosity of less than 1.23. 1 Conclusions. Aromatic polycarbonate according to claim 1, characterized in that it is mixed with 0-10% by weight of titanium dioxide. 10 Polymer blend containing an aromatic polycarbonate and one or more impact enhancers, characterized in that the polymer blend contains the following ingredients: A. as an aromatic polycarbonate, an aromatic polycarbonate with a relative viscosity of less than 1.23, which is provided with end groups derived from 4-cumylphenol. B. one or more means for improving the impact strength, the amount of component A being between 96 and 99.9 weight percent and the weight amount of component B between 0.1 and 4 weight percent, calculated relative to the sum of components A and B 25 Polymer mixture according to claim 3, characterized in that component B consists of a mixture of two agents for improving the impact strength, namely: .8702632 <8-CB-10,312 -15- Polymer mixture according to claim 3 / characterized in that the polymer mixture contains one or more of the following components in addition to the components listed under A 15 and B: one or more agents for improving the flame-retardant properties / one or more stabilizers / a or more agents for reducing droplet (drip) properties in flame tests / one or more pigments / one or more dyes / one or more fillers / one or more reinforcing fibers such as glass fibers / lubricants / release agents / plasticizers. Polymer mixture according to Claim 5, characterized in that the polymer mixture contains as pigment per 100 parts by weight of A + B / 0/1 - 10 parts by weight of titanium dioxide. Polymer mixture according to claim 3 / characterized in that the polymer mixture contains / per 100 parts by weight A + B / 1-100 parts by weight of a polyalkylene terephthalate. Articles formed from the aromatic polycarbonate according to claim 1 or 2 or from the polymer mixture according to any one of claims 2-7. . 8702632. ------- * - ♦ -------- f